how much psi is on the stock wastegate ? 7 or 8 psi my car has an 18g greddy on it and im boosting at 12 to 14 psi on the stock wastegate with no boost controller somethings wrong ? im also getting what feels like boost cut at about 4500 rpms at WOT but if i only push the pedal half way and keep boost under 10 psi i can rev through to redline fine any ideas ?? and yes im running a 3 bar map sensor and my ecu is chipped for it i was thinking a bad wastegate actuator......i couldent find any boost leaks either

 

Are you sure the kit has the original actuator? The Greddy actuator won't hold pressure much past 14psi so a lot of people use a higher base pressure actuator.